PRRX1 promotes malignant properties in human osteosarcoma

PRRX1-TOP2A interaction is a malignancy-promoting factor in human malignant peripheral nerve sheath tumours

BACKGROUND

Paired related-homeobox 1 (PRRX1) is a transcription factor in the regulation of developmental morphogenetic processes. There is growing evidence that PRRX1 is highly expressed in certain cancers and is critically involved in human survival prognosis. However, the molecular mechanism of PRRX1 in cancer malignancy remains to be elucidated.

METHODS

PRRX1 expression in human Malignant peripheral nerve sheath tumours (MPNSTs) samples was detected immunohistochemically to evaluate survival prognosis. MPNST models with PRRX1 gene knockdown or overexpression were constructed in vitro and the phenotype of MPNST cells was evaluated. Bioinformatics analysis combined with co-immunoprecipitation, mass spectrometry, RNA-seq and structural prediction were used to identify proteins interacting with PRRX1.

RESULTS

High expression of PRRX1 was associated with a poor prognosis for MPNST. PRRX1 knockdown suppressed the tumorigenic potential. PRRX1 overexpressed in MPNSTs directly interacts with topoisomerase 2 A (TOP2A) to cooperatively promote epithelial-mesenchymal transition and increase expression of tumour malignancy-related gene sets including mTORC1, KRAS and SRC signalling pathways. Etoposide, a TOP2A inhibitor used in the treatment of MPNST, may exhibit one of its anticancer effects by inhibiting the PRRX1-TOP2A interaction.

CONCLUSION

Targeting the PRRX1-TOP2A interaction in malignant tumours with high PRRX1 expression might provide a novel tumour-selective therapeutic strategy.

Porcine transient receptor potential channel 1 (TRPC1) regulates muscle growth via the Wnt/β-catenin and Wnt/Ca2+ pathways

Transient receptor potential canonical (TRPC) channels allow the intracellular entry of Ca2+ and play important roles in several physio-pathological processes. In this study, we constructed transgenic mice expressing porcine TRPC1 (Tg-pTRPC1) to verify the effects of TRPC1 on skeletal muscle growth and elucidate the underlying mechanism. Porcine TRPC1 increased the muscle mass, fiber cross-sectional area, and exercise endurance of mice and accelerated muscle repair and regeneration. TRPC1 overexpression enhanced β-catenin expression and promoted myogenesis, which was partly reversed by inhibitors of β-catenin. TRPC1 facilitated the accumulation of intracellular Ca2+ and nuclear translocation of the NFATC2/NFATC2IP complex involved in the Wnt/Ca2+ pathway, promoting muscle growth. Paired related homeobox 1 (Prrx1) promoted the expression of TRPC1, NFATC2, and NFATC2IP that participate in the regulation of muscle growth. Taken together, our findings indicate that porcine TRPC1 promoted by Prrx1 could regulate muscle development through activating the canonical Wnt/β-catenin and non-canonical Wnt/Ca2+ pathways.

Identification of potential extracellular vesicle protein markers altered in osteosarcoma from public databases

PURPOSE

Extracellular vesicles (EVs) have become promising biomarkers for cancer management. Particularly, the molecular cargo such as proteins carried by EVs are similar to their cells of origin, providing important information that can be used for cancer diagnostics, prognosis, and treatment monitoring. However, to date, molecular analysis on EVs is still challenging, limited by the availability of efficient analytical technologies, largely due to the small size of EVs. In this work, we developed a computational workflow for in silico identification of potential EV protein markers from genomic and proteomic databases, and applied it for the discovery of osteosarcoma (OS) EV protein markers.

EXPERIMENTAL DESIGN

Both mRNA and protein data were computed and compared from publicly accessible databases, and top markers with high differential expression levels were selected.

RESULTS

Thirty nine markers were identified overexpressed and seven found to be downregulated. These identified markers have been found to be associated with OS on different aspects in literature, demonstrating the usability of this workflow.

CONCLUSIONS AND CLINICAL RELEVANCE

This work provides a list of potential EV protein markers that are either overexpressed or downregulated in OS for further experimental validation for improved clinical management of OS.

TPX2 regulated by miR‑29c‑3p induces cell proliferation in osteosarcoma via the AKT signaling pathway

The present study aimed to investigate the significance of targeting protein for Xenopus kinesin-like protein 2 (TPX2) expression in osteosarcoma. First, the TPX2 expression and survival analysis data were evaluated from The Cancer Genome Atlas (TCGA) database. Next, reverse transcription-quantitative PCR was used to explore the expression of TPX2 in osteosarcoma tissues. The observed potential target relationship between TPX2 and microRNA (miR)-29c-3p was verified using TargetScan and luciferase reporter assays. Kaplan-Meier survival analysis was used to determine associations between TPX2 expression levels and survival prognosis. TPX2 small interfering RNA was successfully constructed and transfected into osteosarcoma cell lines. The effects of TPX2 on osteosarcoma cell proliferation were then detected by MTT assay. In addition, the expression levels of AKT signaling pathway-associated proteins were identified by western blot analysis. The expression of TPX2 was upregulated and the expression of miR-29c-3p was downregulated in osteosarcoma. High expression of TPX2 was linked to a poor prognosis. Using luciferase assay and the miRNA mimic and inhibitors, miR-29c-3p was able to target and repress TPX2, and siRNA knockdown of TPX2 resulted in the inhibition of osteosarcoma cell proliferation by affecting the AKT pathway. Overall, the study showed that miR-29c-3p could inhibit the proliferation of osteosarcoma cells via TPX2 downregulation, and that TPX2 and miR-29c-3p may serve as promising prognostic indicators.

PRRX1 Is a Novel Prognostic Biomarker and Facilitates Tumor Progression Through Epithelial–Mesenchymal Transition in Uveal Melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UM develops and is sustained by inflammation and immunosuppression from the tumor microenvironment (TME). This study sought to identify a reliable TME-related biomarker that could provide survival prediction and new insight into therapy for UM patients. Based on clinical characteristics and the RNA-seq transcriptome data of 80 samples from The Cancer Genome Atlas (TCGA) database, PRRX1 as a TME- and prognosis-related gene was identified using the ESTIMATE algorithm and the LASSO–Cox regression model. A prognostic model based on PRRX1 was constructed and validated with a Gene Expression Omnibus (GEO) dataset of 63 samples. High PRRX1 expression was associated with poorer overall survival (OS) and metastasis-free survival (MFS) in UM patients. Comprehensive results of the prognostic analysis showed that PRRX1 was an independent and reliable predictor of UM. Then the results of immunological characteristics demonstrated that higher expression of PRRX1 was accompanied by higher expression of immune checkpoint genes, lower tumor mutation burden (TMB), and greater tumor cell infiltration into the TME. Gene set enrichment analysis (GSEA) showed that high PRRX1 expression correlated with angiogenesis, epithelial–mesenchymal transition (EMT), and inflammation. Furthermore, downregulation of PRRX1 weakened the process of EMT, reduced cell invasion and migration of human UM cell line MuM-2B in vitro. Taken together, these findings indicated that increased PRRX1 expression is independently a prognostic factor of poorer OS and MFS in patients with UM, and that PRRX1 promotes malignant progression of UM by facilitating EMT, suggesting that PRRX1 may be a potential target for UM therapy.

Enhanced expression of KIF4A in osteosarcoma predicts a poor prognosis and facilitates tumor growth by activation of the MAPK pathway

The present study aimed to explore the prognostic value and role of kinesin family member 4A (KIF4A) expression in human osteosarcoma. KIF4A expression was evaluated in human osteosarcoma tissues from The Cancer Genome Atlas and Gene Expression Omnibus datasets. Reverse transcription-quantitative PCR was then applied to assess KIF4A level in both osteosarcoma cell lines and tissues. The association between KIF4A expression and clinical results in patients with osteosarcoma was detected by survival analysis. MTT assays and colony formation assays were used to evaluate the effects of KIF4A on osteosarcoma cell proliferation. The results indicated that the level of KIF4A was increased and associated with a poor prognosis in osteosarcoma tissues. Knockdown of KIF4A was shown to inhibit osteosarcoma cellular proliferation by affecting the MAPK pathway. The level of KIF4A was high in the human osteosarcoma tissues and this could be considered as a tumor induction gene, which may be used as an indicator of prognosis.

Risk Factors, Prognostic Factors, and Nomograms for Distant Metastasis in Patients With Newly Diagnosed Osteosarcoma: A Population-Based Study

BACKGROUND

Osteosarcoma is the most common bone cancer, mainly occurring in children and adolescents, among which distant metastasis (DM) still leads to a poor prognosis. Although nomogram has recently been used in tumor areas, there are no studies focused on diagnostic and prognostic evaluation of DM in primary osteosarcoma patients.

METHODS

The data of osteosarcoma patients diagnosed between 2004 and 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for DM in osteosarcoma patients, and univariate and multivariate Cox proportional hazards regression analyses were used to determine independent prognostic factors of osteosarcoma patients with DM. We then established two novel nomograms and the results were evaluated by receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

RESULT

A total of 1,657 patients with osteosarcoma were included, and 267 patients (16.11%) had DM at the time of diagnosis. The independent risk factors for DM in patients with osteosarcoma include age, grade, T stage, and N stage. The independent prognostic factors for osteosarcoma patients with DM are age, chemotherapy and surgery. The results of ROC curves, calibration, DCA, and Kaplan-Meier (K-M) survival curves in the training, validation, and expanded testing sets, confirmed that two nomograms can precisely predict occurrence and prognosis of DM in osteosarcoma patients.

CONCLUSION

Two nomograms are expected to be effective tools for predicting the risk of DM for osteosarcoma patients and personalized prognosis prediction for patients with DM, which may benefit clinical decision-making.